Dropped namespacing of test cases

The main benefit is small test ids everywhere, though this is with the
downside of needing longer names to properly prefix and avoid
collisions. But this fits into the rest of the scripts with globally
unique names a bit better. This is a C project after all.

The other small benefit is test generators may have an easier time since
per-case symbols can expect to be unique.

runners/test_runner.h

@@ -37,7 +37,6 @@ typedef struct test_define {
 } test_define_t;
 
 struct test_case {
-    const char *id;
     const char *name;
     const char *path;
     test_flags_t flags;
@@ -50,7 +49,6 @@ struct test_case {
 };
 
 struct test_suite {
-    const char *id;
     const char *name;
     const char *path;
     test_flags_t flags;